Crystal structure implies that cyclophilin predominantly catalyzes the trans to cis isomerization.
Zhao, Y., Ke, H.(1996) Biochemistry 35: 7356-7361
- PubMed: 8652511 
- DOI: 10.1021/bi9602775
- PubMed Abstract: 
The crystal structure of human recombinant cyclophilin A complexed with a substrate of succinyl-Ala-Ala-Pro-Phe-p-nitroanilide (AAPF) has been determined and refined to an R-factor of 0.189 at 2.4 A resolution. The structure revealed only the cis for ...